Economic Stimulus & Three Old Saws

I obviously don't understand macroeconomics (only nanoeconomics) because I'm confused about how borrowing 500 billion dollars from China can be a good thing for our country. Don't get me wrong, I'm not going to say, Oh, it's from China, never mind, I don't want it. I don't think people who refuse to buy something because it's made in China will turn the money down, either. Still, it's a little creepy. I know there's an expression, don't look a gift horse in the mouth--but be ready for that horse to turn around and kick you (April 2009). What about the one concerning the free lunch, as in there is no such thing? I'm just saying that my instinct tells me that the feds are gonna get it back. After all, only two things are certain...